1. Field of the Invention
The present invention relates to an imaging apparatus and an imaging system.
2. Description of the Related Art
A technique is known that in an image sensor device, different gain processes are performed on a pixel signal and the pixel signal is AD (analog-to-digital) converted. With this technique, the converted signal is read out from a memory, and its gain is corrected thereafter, and the resultant AD data is selected based on a signal level, thereby widening a dynamic range. Such technique is disclosed in the Official Gazette of Japanese Patent Application Laid-Open No. 2008-124842.
According to the current on-chip AD converting technique, generally, AD data of a reset noise of a comparator is subtracted from AD data of a pixel signal having the same resolution.
The AD data of the reset noise has a problem on an AD conversion precision that is caused by the reset noise of the comparator. According to the Official Gazette of Japanese Patent Application Laid-Open No. 2008-124842, nothing is disclosed about a correction of the reset noise of a different gain signal in an AD converter.